FHWA Project: Enhanced Prediction of Vehicle Fuel Economy and Other Vehicle Operating Costs

It is critical to improve the VOCs estimation by taking into consideration changes in vehicle technology and extended transportation factors, such as lane numbers, speed limit, horizontal alignment and grade. One of the key tasks for improving VOCs estimation is to develop driving cycles for different vehicles in different transportation scenarios. A driving cycle in the VOCs context is a vehicle speed-time profile, which is normally one hertz vehicle speed. The cycles are a critical input for simulating fuel consumption of different road situations, and are also a required input for advanced fuel consumption estimation tools. The research team has identified the SHRP 2 Safety Data as the new data source for developing driving cycles of different transportation scenarios. The SHRP 2 Safety Data can be used to significantly extend existing driving cycles. The methodology for developing driving cycles has been selected and adjusted with considerations given to the new data source. It is based on the method used by Sierra Research in its ‘Development of Generic Link-Level Driving Cycles’ study in 2008. Data extracted focuses on a total of 4,000 trips. The sample will be stratified evenly between all six SHRP 2 data collection sites. The trips will be longer than 20 minutes. 2,400 trips will consist of driving primarily in urban areas, and the remaining 1,600 trips will be primarily in rural areas. A trip is considered primarily in urban areas if over half the time spent on Link_IDs matched to the trip’s GPS coordinates are in urban areas, and vice versa for trips considered primarily in rural areas. The classification of rural and urban is made in the base map data source which also contains the Link_IDs.